Years ago in the bonsai garden I put up what I thought was the best guess for shade cloth: 30%, meaning, 70% of the light passed through. After several years it was apparent that was not enough, and we switched it with 40%. Since then, in another area, we have put up 50%.
This led to reflection, as tends to happen with bonsai garden owners. We got some heat-nipped plants because my initial guess was off. And then, some summers days are a lot hotter than the average summer day.
The ramping up we did to correct our shade needs suggests a few general ideas, if you’re wondering what percentage of shade you need. For starters:
- Consider choosing shade cloth for the extreme summer day, not the average summer day.
- If 40% is your guess for the average summer day, then consider 50%.
- If under-shaded, one toasty day can roast trees beyond recognition
30% shade cloth
How do we arrive at that initial guess? This line from a manufacturer made me smile: Usually a shade percentage of 30-50% is ideal for vegetables, while 80-90% is ideal for sheltering people.
As a general sliding scale for bonsai, to be adjusted according to climate:
- 0-30% for sun-loving conifers, like pines and junipers
- 40-60% for deciduous trees and flowering accent plants
- 70-80% for moss, ferns, and non-flowering accent plants
In very hot climates with intense sun, some shuffling could happen. In those climates conifer bonsai, for example, can be moved into the 40-60% shade camp. Very small bonsai also need more shade.
For perfectionists:
- To nail the ideal sun/shade balance, consider overlaps
- A second shade covering, maybe 20%, can be pulled over the everyday summer cloth
- This can add critical protection for periods of extreme sun and heat
70% shade cloth, for shade-loving plants and extreme climates
In the middle of a big fry added sun protection banks.
On the other hand, overcompensating with shade does no favors for a plant. Plants have a specific light need, and if that is not met they can get weak. If 20% shade cloth doesn’t quite do it, resist the impulse to jump to 70%.
Next up in this short series on shade cloth, in Part II, we look at whether the color of shade cloth matters.
For more about shade cloth, try these previous posts: Podcast about Shade Cloth, and Not Just For Sun.